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Scientists Reveal Responses of Carbon and Nitrogen cycles to Grassland Degradation



Grassland ecosystem in Qinghai-Tibetan Plateau (QTP) is of great significance to soil and water conservation, regional and global climate, and carbon (C) sequestration. However, approximately 90% of the alpine grassland on the QTP has become degraded since the 1990s, as a result of climate change and overgrazing activities.  

As grassland degrades, changes in the vegetation community and soil properties influence the C and N cycling. In recent years, δ13C and δ15N are extensively used to understand the biogeochemical mechanisms that moderate ecosystem C and nitrogen (N) processes.  

Although previous studies have reported the effects of grassland degradation on the soil δ13C and δ15N, they only focused on one degradation stage, and the degradation effects on the vegetation δ13C and δ15N still unclear. 

Recently, scientists from Northwest Institute of Eco-Environment and Resources (NIEER) of Chinese Academy of Sciences selected five degradation stages including intact, slight degradation, moderate degradation, severe degradation, and very severe degradation to explore the degradation effects on C and N cycles on the QTP. 

The study indicated that alpine grassland degradation increased both the δ13C and δ15N of vegetation and soil, particularly in severe degradation and very severe degradation status. 

Further study showed that more forbs species occurred in degraded alpine grassland, relative to intact grassland, and these plants strongly controlled vegetation and soil δ13C enrichment. 

Besides, changes in community composition through its effect on the soil C/N strongly controlled vegetation and soil δ15N enrichment as grassland degradation became worse on the QTP. 

This study has been published on Land Degradation & Development recently entitle “Plant community changes determine the vegetation and soil δ13C and δ15N enrichment in degraded alpine grassland”. Dr. LI Chengyang is the first author and associate Prof. PENG Fei is the co-corresponding author. 





Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resource, Chinese Academy of Sciences, 320 Donggang West Road, Lanzhou 730000, Gansu, PR China. 


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